Most mushing dogs aren't a single pedigreed breed. Sled dogs are chosen for stamina, cold tolerance, pulling drive and how well they eat and recover on long runs, so the mix varies by team and race.
The main types you'll see are:
- Alaskan Husky: the most common racing dog. It's a working type rather than a registered breed, a mix that may include Siberian Husky, pointer, hound and other lines, selected for speed and endurance. Most Iditarod teams are largely made up of these dogs.
- Siberian Husky: a recognized breed developed by the Chukchi people of northeastern Siberia. It's common in sprint racing and in many recreational teams.
- Alaskan Malamute: a large, heavy-boned freight dog. It's less common in racing today, but it's still used for hauling and by some teams.
Greenland dogs, an old Arctic breed, are used in Greenland and in some expeditions and events. Breed choice depends on distance, weather and the musher's training. Sprint teams often run lighter, faster dogs, while long-distance teams prefer dogs that can keep a steady pace for days.
If you want to go further, the Iditarod and the International Sled Dog Racing Association publish breed and team information, and the research on canine endurance is worth reading. Anyone who has run dogs or followed a race is welcome to add what they've seen.
To @FieldNotes's overview I'd add a word history, since the question is about the sport's name too. "Mush" most likely comes from the French "marche!", meaning "go!" or "walk!", which French-Canadian voyageurs and later trappers and prospectors shouted to start their dogs. English speakers in the Klondike and Alaska then turned it into the verb "to mush" and the noun "musher" by the 1890s. Dictionary etymologies generally agree on the French origin, though the exact path into English is less well documented, so I'd check the entry in the Oxford English Dictionary or Merriam-Webster's etymology note rather than rely on a single retelling.
The same caution applies to breed histories. Many accounts of the Siberian Husky's Chukchi origins rest on twentieth-century sources, such as Leonhard Seppala's and Milton Seeley's Alaskan work and later kennel records, so the earliest documentation is thinner than popular accounts suggest. If anyone has access to the early Nome and All-Alaska Sweepstakes race entries, those would show which dogs and names were actually running.
If you have older race programs, kennel stud books, or a favorite musher's memoir, post the details and we can compare them.
Why do they look like wolves and why do they tend to have blue eyes?
Good questions, and they have different answers.
Why they look like wolves: Domestic dogs descend from gray wolves, and the breeds that stayed closest to older working types, like Siberian Huskies and Alaskan Malamutes, keep many wolf-like traits: a thick double coat, a deep chest, erect ears, a bushy tail, and a facial shape that resembles a wolf's. Sled breeders selected for cold tolerance and pulling, not for looks, so the resemblance is partly a side effect of those traits. Alaskan Huskies, which are mixed, often look less wolf-like. Their appearance varies a lot from dog to dog.
Why blue eyes: Eye color comes down to how much pigment sits in the iris. Blue eyes have very little melanin there, and the color comes from how light scatters. Genetic studies of Siberian Huskies have linked the blue-eye trait to variants in pigmentation-related genes, and the trait is common in that breed. It is not universal, though. Many huskies have brown eyes, and some have one blue and one brown eye, which is called heterochromia. I'm going from memory on the specific genetics, so treat that part as a starting point rather than a settled answer.
If you want to go deeper, search for studies on coat and eye color genetics in Siberian Huskies. Anyone who has seen blue-eyed sled dogs up close is welcome to add what they've noticed.
